Seed Oils Are Not Bad For You

So-called “health influencers” – self-appointed health gurus spreading their unvetted opinions about health through social media, have apparently decided that seed oils are bad for you. Our chief health guru, RFK Jr, even blames seed oils for the obesity epidemic (based on the flimsiest of evidence and logic, which is his MO). I’m not exactly sure where this demonizing of seed oils originated, but health gurus love to demonize “bad” food while promoting their own brand du jour of “superfoods”, so they all quickly jumped on the anti-seed oil bandwagon.

However, if we look at the totality of the evidence we find that seed oils are – food. That’s right, they are a source of nutrition and calories, and as long as you follow the golden rule of everything in moderation, this is not something you need to worry about or expend resources trying to deal with.

In fact seed oils, if anything, are at the healthier end of the spectrum when it comes to food in general and oils in particular. This is why nutrition scientists were puzzled over this particular fad because now they are picking on an overall healthy food. This should not have been surprising, however, because this is how health influencers operate – misinterpret preliminary or partial information and leap to ridiculous conclusions, as long as this gives you something to scare people about or something to sell. It’s good for engagement – learn the one food you must avoid to stay healthy. It’s clickbait health advice.

The TLDR version of this post is – seed oils are just fine, in fact it’s good that your diet contains some seed oils, don’t worry about it, go on with your life. For those who want some more details, read on.

First, whenever we talk about eating fats or oils we need to consider their effect on cholesterol and therefore heart and other vascular disease. Here, seed oils appear to have a beneficial effect on our cholesterol. They contain omega 6 (a polyunsaturated essential fat) such as linoleic acid, which reduces LDL, the bad cholesterol. That’s a good thing.

A recent systematic review found that increased levels of linoleic acid reduces the risk of fatal coronary heart disease. This aligns with other research finding a reduced risk of heart disease with lower LDL, which omega 6 does.

We also can consider the ratio of consumed omega 3 (the other good fat) and omega 6. Pre-industrial societies had a ration of 6:3 around 4:1. Industrialized diets, which do contain more seed oils, can be closer to 20:1. The claim is that this increases both inflammation and clotting. This is one chain of logic that leads some to argue for reduced omega 6 intake, but there are numerous problems with this logic.

First, this is basic science information, which is always difficult to apply to whole organisms. This is where many health gurus fail – they extrapolate from the petri dish to human health, but this is not a straight line. We need to look at clinical evidence, and whole organism evidence, to see what is actually happening. We find, for example, that omega 6 is associated with decreased inflammatory markers, if anything, although we do need more research.

The same is true of blood clotting. There are plenty of pro and anti-clotting factors in the body, maintaining an optimal balance (in healthy individuals). Pushing this system away from clotting reduces the risk of strokes and heart attacks, but increases the risk of bleeding (and vice versa). There is no one without the other. So saying that any clotting factor is necessarily a bad thing misses the point about this balance. What we need to know is – what is the net clinical effect.

In the end, there is no evidence that having a higher 6:3 ratio is a health risk for inflammatory or vascular disease. What is very likely true is that the body, which is a dynamic homeostatic system, just deals with it without any significant effect. Further, if you want to make your 6:3 ratio closer to pre-industrial societies, the best way to do this is to increase your omega-3 intake, not decrease your omega-6 intake, since both oils are overall heart healthy.

The anti-seed oils warriors also claim that cooking or heating seed oils can result in the formation of toxic chemicals (such as aldehydes). There may be an issue with repeatedly heating seed oils to high temperatures, such as in a restaurant deep fryer, but not with home use. Again, there is no proven risk here, just something requiring further study. There is also a simple way to avoid any potential risk – swap out the oil in deep fryers a bit more frequently.

Some point to chemical processes in the industrial formation of seed oils (rather than cold pressing, which is more costly), but anything added in this process is later removed to insignificant levels, and so again there is no evidence of risk or harm.

Finally, seed oils have been caught up in the anti-ultra processed food trend. This is an issue unto itself, but the quick version is that – processing food is not in itself harmful or a health risk. The only thing that matters is the final product. It is true that many processed foods are high in salt, sugar, and calories, and that’s the real issue. Focusing on the processing is missing the real issue, as is demonizing seed oils by association.

Based upon all the evidence, what are some bottom line actionable conclusions?

• First, feel free to consume and use seed oils at home. Plant-based oils are generally healthy, and again if you follow the rule of – everything in moderation – that is a simple and effective approach to most nutritional questions.

• If you are concerned about your 6:3 ratio in your diet, then increase you omega-3 intake, which most people could benefit from anyway. Do not avoid omega-6. Doing so is far more likely to be harmful than helpful to your health.

• We may need further research and perhaps regulation in terms of how restaurants use deep fryer oil. However, again, if this is a concern you probably should eat less fried foods.

• Do not listen to anything RFK Jr. has to say. He is a dangerous health crank and conspiracy theorist who does not know how to interpret scientific evidence.

• An extension of the RFK rule is – do not get your health advice from “influencers” on social media. There are plenty of reliable academic and professional sources of information online.